The invention relates to a method for introducing at least one pipe for at least one optical cable into a solid bed with the aid of a laying device, wherein at least one groove is milled or cut in the bed and the at least one pipe is inserted in the at least one groove.
The present invention further relates to an apparatus for introducing at least one pipe for at least one optical cable into a solid bed, comprising a milling or cutting device for milling or cutting at least one groove in the bed and at least one drum on which the at least one pipe to be laid is wound.
Nowadays, many households throughout the world are still connected via copper cables with corresponding data networks for the transmission of telephone, television, or computer signals. Whereas the various communication networks of different information services have already gradually been converted from copper to glass fibre cable and data transmission rates have thereby been able to be substantially increased, the conversion of copper cables to glass fibre cables at the end consumer is still lagging behind. As a result of innovative methods such as, for example, the trenchless removal of wires from cable tubes described in EP 1 362 398 A, the retrofitting of lines to the end consumers is now possible with reasonable expenditure. If the copper tube of a buried cable freed from the copper wires is used to receive optical cable, the household would be separated from the respective communication networks for a certain time interval between the removal of the copper cable and the relaying of the optical cable. Since such a state would be unacceptable at the present time, it is necessary to provide for an alternative data connection at least during this time interval.
Wireless systems are used for bridging the data connection, via which the end consumer is connected to the desired communication networks. However, the expenditure for the corresponding transmitter and receiver is relatively high. The corresponding components must also be supplied with electrical energy via batteries and suitably protected against theft.
Alternatively to this, a bypass data line can be installed, via which the end consumer is connected to the corresponding communication networks during the time of the retrofitting of the data line. Freely running data lines which per se could be laid rapidly and easily have not proved successful on account of their susceptibility to weather and destruction. The expenditure for the laying of buried cables, on the other hand is again very high and frequently not economically sustainable.
For this reason, methods and apparatuses for the rapid and cost-effective introduction of optical cables into a solid bed have already been developed. For example, EP 0 861 455 B1 describes a method for introducing at least one optical cable into a solid bed by which means the laying expenditure can be reduced.
EP 1 619 767 A1 describes such a method for laying optical cables in a solid bed.
EP 0 162 623 A 1 relates to a method for laying drainage pipes in the ground, where no measures are taken to protect the pipe from damage.
US 2004/165957 A1 relates to a method for laying a tube for optical cables in a solid bed, wherein the tube is protected with a jacket of compressible material.
Finally, DE 38 05 344 A1 discloses a universally applicable apparatus for constructing general trenches.
In the known laying methods, a groove is usually milled and cut in the solid bed, then the at least one optical cable or a pipe for receiving at least one optical cable is inserted in the groove and a corresponding filler material, such as for example, bitumen is poured into the groove over the cable or a pipe receiving the optical cable and hardened. Although these laying methods can be carried out more rapidly and inexpensively compared with conventional methods for laying buried cables, the expenditure is nevertheless relatively high. Also, as a result of the inadequate retention of the optical cable or pipe in the groove, an undesirable emergence of the optical cable or pipe from the groove occurs in some places, before the filler material is hardened. In consequence, some damage or destruction of the optical cable and therefore an interruption of the data line can occur.
When using hot bitumen for filling the groove, damage to the optical cable or the pipe surrounding the optical cable can additionally occur.
A further disadvantage in the known methods is that frequently a groove that is too deep is cut in the bed and for example, a road surface is thereby cut through in places so that the pipe for the optical cable runs unprotected in loose earth located thereunder and can be damaged. In addition, when cutting through an asphalt surface, partial breakup of the asphalt surface may occur, which in turn must be renovated in time-consuming and expensive working steps.